The role of the pituitary hormone, ACTH, on macrophage has been the focus of this project. The results indicate that ACTH can stimulate macrophage cell lines to grow in vitro and that ACTH in conjunction with lipopolysaccharide (LPS) can cause the secretion of tumor necrosis factor. The mRNA has been isolated from these stimulated cells to determine if the stimulation of TNF secretion occurs at the genetic level.